The present invention relates to a method of controlling the movement of a position indicating item displayed on a screen in accordance with an output signal of control means including a pressure-sensitive resistor which outputs a signal whose level varies depending upon a pressing force applied to an operating element, a computer-readable storage medium on which a computer-executable program for implementing the method of controlling the movement of a position indication item is stored, and an electronic device including such a program.
Electronic devices such as a video game machine generally include a main unit connected to a television set used as a display and a control means such as a controller connected via a cable to a the main unit.
The main unit includes a disk drive for reading a game program stored on a storage medium such as an optical disk, an image processing apparatus for displaying a character together with a background image on the screen of the television set in accordance with the game program stored on the storage medium, and a storage device for storing the progressive status of a game.
The control means includes a plurality of control buttons which are operated by a user in various manners to control the motion of a character displayed on the screen of the television set connected to the main unit of the video game machine. One known controller for use in such a video game machine includes a direction command button in a cruciform or circular form disposed on the left side of the upper surface of the controller and also includes a plurality of multi-purpose buttons disposed on the right side.
When a game program is executed by such a video game machine, an initial screen is displayed so that a user can select whether the game program is executed from its beginning or continued from the state indicated by the game status data stored in the storage device. When the game program is executed from its beginning, a screen for registering a user name or the like to identify the game status data to be stored in the storage device is displayed. Furthermore, when the game program is being executed, a screen for selecting items used by a character is displayed.
Via such a screen, the user can start the game program in a desired state or can select an item used by a character by operating various buttons disposed on the controller so as to move a position indicating item such as a pointer or a cursor and select one of options displayed on the screen.
However, the conventional control buttons such as the direction command button and the multi-purpose button disposed on the control means are designed to output a digital signal having either a high or low level. Therefore, in order to move the position indicating item to a desired menu option using the direction command button or the like, it is required to operate the direction command button as many times as there are menu options. In particular, when a user name or the like is registered in the storage device via the initial game screen by selecting kana characters from characters displayed on the screen using the conventional control means, it is required to operate the direction command button a large number of times. Thus the user has to perform a troublesome operation for selection.
It is an object of the present invention to provide a method of controlling the movement of a position indicating item displayed on a screen so as to quickly move it in accordance with an output signal of control means including a pressure-sensitive resistor thereby making it easier to make a selection with the position indication item. It another object of the present invention to provide a computer-readable storage medium on which a program for implementing such a method is stored. It is still another object of the present invention to provide an electronic device including such a program.
According to an aspect of the present invention, to achieve the above objects, there is provided a method of controlling the movement of a position indicating item displayed on a screen in accordance with an output signal of control means including a pressure-sensitive resistor which outputs a signal whose level varies depending upon a pressing force applied to an operating element, the method comprising: a signal level detection step for detecting the signal level of the signal output by the control means; a moving speed setting step for setting the moving speed of the position indicating item displayed on the screen in accordance with the signal level detected in the signal detection step; and an item moving step for moving the position indicating item at the moving speed set in the moving speed setting step.
Herein, the position indicating item refers to an item which indicates one of menu options displayed on a screen thereby allowing a user to specify a desired option. Examples of such a position indicating item include a cursor and a pointer displayed on an initial screen of a game program or displayed when the game program is being executed. The position indicating item may also be realized by highlighting a particular one of the plurality of options displayed on the screen.
The method of controlling the movement of the position indicating item may be implemented by a program stored on a storage medium on which a game program is stored. Furthermore, the respective steps described above may also be implemented by signal level detection means, moving speed setting means, and item movement control means, disposed in an electronic device such as a video game machine including a processing device and a memory device. In this case, the respective means may be realized by a program stored in a memory device such as a ROM (Read Only Memory) such that when the electronic device is powered on, an operating system is first loaded on the processing device and the above-described means are then loaded.
In the present invention, the level of the signal output by the control means including the pressure-sensitive resistor is detected in the signal level detection step, and the moving speed of the position indicating item is set depending upon the signal level detected in the signal level detection step. That is, the moving speed of the position indicating item is changed depending upon the pressing force applied to an operating element of the control means so that the position indicating item can be quickly moved in the item moving step thereby making it easier to make a selection with the position indicating item.
Preferable, the method of controlling the movement of a position indicating item further comprises a signal determining step for determining, when one of options displayed on the screen is selected by moving the position indicating item, whether the signal whose signal level has been detected in the signal level detection step should be converted to a two-level signal, in accordance with the number of options displayed on the screen.
The signal determining step may convert the signal whose signal level has been detected in the signal level detection step into a two-level signal depending upon whether the signal level detected by the signal level detection step is higher than a predetermined threshold value.
That is, when a small number of options are displayed on the screen, the position indicating item may be moved by a turning-on/off operation using the control means in a similar manner as with the conventional control means, without causing a problem. Therefore, the signal determining step makes it possible to skip the moving speed setting step for setting the moving speed of the position indicating item thereby allowing simplification of the process of controlling the movement of the position indicating item.
The signal output by the control means is preferably a digital signal obtained by converting an analog signal output by the pressure-sensitive resistor.
It is desirable that the control means include an A/D converter for converting the analog signal output from the pressure-sensitive resistor to a digital signal.
If the control means outputs a signal in digital form, the signal output from the control means becomes insensitive to noise. As a result, it becomes possible for the signal level detection step to accurately detect the signal level corresponding to the pressing force applied to the operating element, and it further becomes possible to move the position indicating item at a correct moving speed depending upon the pressing force applied to the operating element.
Furthermore, the signal output by the control means is preferably a signal obtained by correcting the upper and lower limits of an analog signal output by the pressure-sensitive resistor to corresponding calibrated levels.
This ensures that the output signal level precisely corresponds to the pressing force regardless of a variation or a deviation in the resistance of the pressure-sensitive resistor.
According to another aspect of the present invention, there is provided a computer-readable storage medium including a computer-executable program stored thereon, the program implementing a method of controlling the movement of a position indicating item displayed on a screen in accordance with an output signal of control means including a pressure-sensitive resistor which outputs a signal whose level varies depending upon a pressing force applied to an operating element, the program comprising: a signal level detection step for detecting the signal level of a signal output by the control means; a moving speed setting step for setting the moving speed of the position indicating item displayed on the screen in accordance with the signal level detected in the signal detection step; and an item moving step for moving the position indicating item at the moving speed set in the moving speed setting step.
Preferably, the program stored on the storage medium further comprises a signal determining step for determining, when one of options displayed on the screen is selected by moving the position indicating item, whether the signal whose signal level has been detected in the signal level detection step should be converted to a two-level signal, in accordance with the number of options displayed on the screen.
According to still another aspect of the present invention, there is provided an electronic device comprising: control means including a pressure-sensitive resistor which outputs a signal whose level varies depending upon a pressing force applied to an operating element; signal level detection means for detecting the signal level of the signal output by the control means; moving speed setting means for setting the moving speed of the position indicating item displayed on the screen in accordance with the signal level detected by the signal detection means; and item moving means for moving the position indicating item at the moving speed set by the moving speed setting means.
Preferably, the electronic device further comprises signal determining means for determining whether the signal whose signal level has been detected by the signal level detection means should be converted to a two-level signal, in accordance with the signal level and the number of options to be selected with the position indicating item.
Preferably, the pressure-sensitive resistor has a conduction characteristic which varies depending upon an applied pressure. Alternatively, the pressure-sensitive resistor may include a resistor and a conductive element the contact area between which varies depending upon an applied pressure.